1. Field of the Invention
The present invention relates to display devices, and particularly to a display device with built-in USB (Universal Serial Bus) ports, wherein via the USB ports the display device powers USB devices.
2. Description of the Related Art
A wide variety of computers have been configured with USB ports; for example, desktop, laptop, and notebook computers. Via the USB ports, the computers can communicate with external USB devices.
The power pins of the USB ports provide approximately +5V voltage. Recently, computers have been used to power or even charge external devices by utilizing the USB ports. The power supplied to an external device is typically obtained from a host of the computer. For example, via a USB port built into a display device of a computer, the computer can utilize the power from its host to power or even charge an external USB device.
However, when the power is supplied by the host, the power supply to the external device through the computer is practicable only when the host is in a normal working mode. Once the host enters into a power-saving mode or is powered off, the power supply to the external device is immediately cut off.
In addition, most display devices have their own power supply independent from the corresponding host. These display devices have their own potential ability to power external devices.
Therefore, there is a need for a display device with a USB port, whereby when a corresponding host is in a mode such as a power-saving mode or a power off mode, the display device can take over the power function from the host to power external USB devices.